How to use this tool
- 1Pick a pattern: gradient, horizontal/vertical lines or checkerboard.
- 2Tap 'View full screen'.
- 3Check that the gradient is smooth and look for fixed lines.
- 4Tap the screen to exit.
About this test
The brightness gradient (black to white) reveals uniformity problems and color banding, common on failing or low-quality panels. Thin-line patterns help locate dead lines and display connection faults.
It complements the dead pixel test: that one finds dots, this one highlights whole-row defects and backlight bleed on LCD panels.
Privacy: this tool runs entirely in your browser. No image, audio or device data is recorded or sent to any server.
Frequently asked questions
What is banding?
Visible bands where a smooth color transition should be. It can be a panel limitation or a sign of defect.
I found a fixed line, can it be repaired?
Fixed lines usually mean a defect in the panel or the display flex cable, which typically requires a screen replacement.